Major advances have been made in recent years in computing and telecommunications electronic hardware, and in part because of the heavy investment in research and development in these high technology areas, advancements are now being pursued in the field of battery design.
The compelling objectives of increasing battery capacity while reducing their volume and weight and meeting ecological concerns are now being achieved inter alia through the introduction of nickel metal hydride (Ni-MH) batteries. Such batteries offer higher energy densities than Ni-Cad batteries enabling downscaling of the batteries while enhancing the run time of the batteries. A Ni-MH battery has approximately double the capacity of an equivalent sized Ni-Cad battery.
Although Ni-MH batteries have greater capacity per unit size and weight and are more ecologically acceptable, care must still be taken with these batteries since they are prone to risk of oxygen or hydrogen build up. Oxygen is normally generated at the positive electrode toward the end of charging of the Ni-MH cell and must be consumed to avoid pressure build up. Hydrogen is generated throughout the charging of the battery and is normally stored as the hydride of the metal alloy anode. Mistreatment of the battery may, however, lead to build up of hydrogen. Build up of either of these gases can represent a significant hazard.
A relatively slower rate of charging than Ni-Cad batteries and lesser high drain capability represent further limitations of NiMH batteries and neither NiCad nor NiMH batteries exist with high current yield (e.g. 64 Amps) or which can be rapidly charged to such a level (e.g. in as little as four hours). This severely limits the usefulness of these batteries. Furthermore these batteries are rendered useless at markedly sub-zero ambient temperatures.
It is a general objective of the present invention to overcome or significantly mitigate one or more of the aforementioned serious problems.
There is, furthermore, a need for a rechargeable battery that is highly compact yet adapted for use in hostile environments and suited to being left ‘outdoors’ unattended for many hours, having the ability to store a high level of charge for delivery over prolonged periods. Applications for the battery are many and diverse and include, for example, powering perimeter security installations as well as providing power to remote sensing and surveillance equipment. In some cases the installations involved may be many miles, even hundreds or more miles remote from the nearest technicians and the problem of maintaining an up to date knowledge of the status and performance of the batteries can be acute.
In this general technical field there is little and inadequate current provision to enable remote battery monitoring and the present invention seeks to overcome these shortcomings.